1. Field of the Invention
The present invention relates to a process for threading a material web onto a reel, e.g., in a paper machine, The being of the material web to be threaded is guided around a drum that precedes the reel and, before being threaded onto the reel, is supplied to a preparation station, e.g., a pulper. The invention also relates to a device for performing such a process.
2. Discussion of Background Information
Threading of a material web onto a reel is required, for example, at the beginning of a winding process to wind a beginning of the web onto an empty reel. Likewise, a threading process is required in the event of a web break to thread a new web beginning onto either a wound reel or an empty reel. For this purpose, the empty reel or the wound reel is placed onto the drum after the previously wound reel has been removed.
Before the beginning of the web is threaded, it is supplied to a pulper in which the threading tip of the material web is removed. The threading tip is thus discarded into the pulper immediately after being guided around the drum that precedes the reel. After the material web has widened out with its continuous disposal of it into the pulper, the material web is cut and only then is it threaded onto the empty or wound reel,
One problem with the above-noted process is that the material web threads itself onto the reel before being cut. This problem occurs to a greater extent at high machine speeds.
Attempts have been made to solve this problem by embodying the drum preceding the reel as a suction drum, which produces a negative pressure within the drum that acts on the material web through corresponding openings in the drum to secure the material web against the drum. However, this arrangement can, to a large extent, prevent a self-threading of the material web onto the wound reel or the empty reel. Moreover, the negative pressure inside the drum makes it more difficult to remove the web for disposal into the pulper.